Complex IR absorption surface

I have a problem a bit tricky to solve which deals with Infrared absorbers.
In my setup experiment, some IR radiations are emitted, let's say black body radiations at 300K, so IR wavelengths centered on 10,6µm.
I want to absorb them (entirely) by a surface (at about 77K) made of several layers to prevent my system from any heating. Consequently, I also want to prevent from IR reflection on this surface.

Maybe some of you can help me to "build" this surface.
For the moment, I have been thinking about a surface made of : (from outer to inner layer)